Alex,
Whats the difference to taking a blood transfusion and just drinking blood
The former is a tissue transplant
The latter is an act of cannibalism
That is a substantial distinction, physically, ethically and morally.
...believers are told to abstain from blood
In the context of a dispute over whether Christians should be circumcised and follow the Law, the ruling was to:
"Keep abstaining....from blood"
I'm quoting your own NWT, which in my opinion, is quite accurate here.
The clear connotation is the continuation of an existing prohibition that was already being kept.
And this is not simply my opinion. As I've already pointed out, your own church publications acknowledge that this was in fact, a reference to the eating of blood as forbidden in the Law.